1. Field of the Invention
The invention relates to the field of data processing systems. In particular the invention relates to a method and system for an entitlement management system for managing the entitlement, harvesting, and distribution of CPU processor cycles.
2. Related Art
The speed and efficiency of many computing applications depends upon the availability of processing resources. To this end, computing architectures such as the ‘virtual machine’ design, developed by International Business Machines Corporation, share common processing resources among multiple processes. Such an architecture may conventionally rely upon a single computing machine having one or more physical controllers, or central processing units (CPUs). The CPUs may execute software configured to simulate multiple virtual processors.
Such multiprocessor environments support the conceptual practice of logical ‘partitioning’. Partitioning provides a programmed architecture suited for assignment and sharing of assets. A partition may logically comprise a portion of a machine's CPUs, memory, and other resources, as assigned by an administrator. As such, an administrator may allocate portions of resources to more than one partition. Each partition may additionally host an operating system, in addition to multiple virtual processors. In this manner, each partition operates largely as if it is a separate computer.
Each virtual processor may access many of the physical resources of the underlying physical machine. Exemplary resources may include memory assets and hardware registers, in addition to the CPUs. Virtual processors may additionally share a priority scheme or schedule that partially dictates allocation of processing cycles between virtual processors. An underlying program called a ‘hypervisor’ or partition manager, may use this scheme to assign and dispatch CPUs to each virtual processor. For instance, the hypervisor may intercept requests for resources from operating systems to globally share and allocate them.
In this manner, virtual processors act as logical threads of execution for a host partition. As such, the virtual processors can separately execute instructions, while sharing resources. By duplicating the utilization of physical assets, a partitioned environment can promote better performance and efficiency. The programmable flexibility of partitions may further allow them to respond to changes in load dynamically without rebooting. For example, each of two partitions containing ten virtual processors may take over all the CPUs of a shared physical system without requiring a re-boot or operator intervention.
To promote proportionate resource allocation, an administrator may place constraints on the number of resources accessible by a virtual processor. For instance, the hypervisor may be constrained by a rule never to dispatch more than fifty percent of available CPU resources to a certain processor. Similarly, the hypervisor may ensure that a virtual processor's use of a CPU does not exceed a specified duration. In this manner, the virtual processor may be allocated a ‘time slice’ of a CPU, at the expiration of which, the hypervisor may pre-empt the virtual processor's use of the CPU. Through similar programming, a complex application can theoretically be distributed among many processors instead of waiting on a single processor.
To illustrate further, referring now to FIG. 1, there is shown a simplified diagram of a data processing system 100 in which a hypervisor 110 operates. The hypervisor layer 110 is responsible for validating operating system 105 requests to use shared platform resources 115, such as a physical processors 125, memory 120, cache 130, input/output slots 135, and expansion boards 155 etc., thus ensuring the integrity and isolation of each partitioned system. Each of these components is connected via a series of interconnection fabrics 140.
Operational management for the platform is performed using a hardware management console (HMC) 160. The HMC 160 interfaces with a processor 145 and is a set of firmware tools, optionally running on replicated hardware that manages platform resources via messages to the hypervisor 110 and the operating system 105 partitions. The HMC 110 creates the initial configuration definitions, control boot, and termination of the various partitions, and provides virtual console support. A partition, which can either be a dedicated or a shared processor partition, views its physical processors 125 as virtual processors. The virtual processor of a dedicated processor partition has a virtual processor allocated to it, while the virtual processor of a shared processor partition shares the physical processors of the shared processor pool with virtual processors of other shared processor partitions.
A problem occurs when there is a need to prioritize the entitlement and management of CPU processor cycles for particular applications, types of business functions or tasks which require access to more CPU resources than other types of tasks. For example, a transaction processing system for a bank can be considered a high priority application because it needs high availability access to processing resources for most of the day in order to meet customer demand. Now compare this to a database query system for a back-office application which is used only for a few hours a day and only requires a small amount of CPU processing resource to satisfy its processing needs. Thus, there is a need to allocate CPU resources to particular applications, functions or tasks etc on a weighting basis, for example, on ‘my need is greater than yours basis’. Another problem which arises is how to manage the entitlement issues and harvesting of spare processing cycles such that one group is not starved of CPU processing resources and another group has an abundance of spare CPU processing cycles, after its own entitlement request has been fulfilled, such that the spare CPU processing resources do not go to waste.